I am so sorry your husband has RSD. Unfortunately some doctors do NOT know anything about it. To remove your husband from a medication that gives some quality of life is horrible. That is NOT what doctors took their Oath for. You must find a doctor who will continue to treat your husband.
You mentioned Ketamine. Did he receive infusions? If you post near where you live, perhaps someone on NT will have the name of a pain specialist that knows about RSD. Continued appropriate pain management is essential for a decent life. I will keep you and your husband in my thoughts and prayers. ginnie